Sexing Cannabis Plants

Sexing

Sexing is an important part of the growing of marijuana. It is the source of much needless worry for beginning growers. You want to sex your plants to remove males. Male plants have low potency. Those interested in the psychoactive effects will want to cultivate the females for their flowers. In the 1960's people used the leaves, stems, and fertilized flowers effectively medicinally with excellent results. The leaves or "shake" can be smoked with good results. The flowers are the most potent especially when not allowed to be fertilized..

A virginal female plant will direct the bulk of its energy later in its growth phase into developing the flower buds and swelling them with the resin that carries the bulk of marijuana's potency. The plant does this so that the large sticky flowers are more likely to catch pollen. If the flower is pollinated it will instead direct the bulk of its energy to seed production. This is where low quality dirt weed comes from. If you have seedy pot, it is dirt weed. The more seeds contained in the pot the lower the quality. And of course seeds add dramatically to the weight since they weigh more than the bud itself, this is sharply contrasted with stems that are mostly water weight and have a negligible weight compared to the bud.

Plants generally should demonstrate their sex one to two weeks into flowering. During the first ten days of flowering there is very little need for concern about males pollinating your crop. Additionally, if you reproduce by cloning you will only have to worry about males once.

Identifying the Male

Males can be identified by looking at the nodes where leaf and branch stems connect with the main stalk. Male flowers will contain balls somewhere between the size of a marijuana seed and a popcorn seed. One ball is not definitive since female pistils sometimes split from a small single ball that opens. But two or three balls in a cluster is sure confirmation that you have a male. Males should be removed and destroyed to prevent them from releasing pollen. The pollen transports easily so the males can not be safely grown anywhere that shares an A/C or ventilation system unless special precautions are taken. The males for the most part show their sex before the females. They appear often to be a lanky less bushy plant than the female. It takes about a week after showing their sex before pollen is released, making it easy to separate from the female. Males can be used to make hashish, though it will require a larger amount of leaves to make hashish or canna-butter (cannabis butter).

Identifying the Female

Females are very simple to identify. They sprout white hairs. A small ball will form and split and two tiny white hairs like translucent threads will split out. These hairs are called pistils and intended to catch pollen. Later when the plant is not pollinated these hairs will change color.

Pistils may guarantee that your plant is not a male but your plant could still be a hermaphrodite. You must watch plants grown from seed carefully for male flowers and even a trusted clone if it has undergone stress such as light during its dark period, lack of watering, or being left to flower far past maturity.

Pre-flowers and Early Sexing

During pre-flowering, plants start to exhibit their sex. As a grower, you should be hoping for as many females as possible. Pre-flowering occurs at the node regions. Towards the end of vegetative growth you need to check your plant nodes for what is called calyx development. A clone will carry the exact same genetic make up as the plant it came from, so if you know your clone's history you will already be able to predict it's sex.

First Early Sexing Method
If you've been growing the same strain and all the seeds were started at the same time, then you may notice that some plants are taller than others: the smaller plants tend to be female and the taller ones tend to be male. You can separate these plants into two sections in order to see how good your guesswork was when you do definitively identify sex. The other thing to note is that male plants generally start to pre-flower before females. If you have taller plants that are producing new growths before the smaller ones then the taller plants are probably male.

Second Early Sexing Method
A good way to identify plant sex at an early date is to examine the calyx* with the aid of a very fine magnifying glass. If the calyx is raised on a small, short stem then it's probably a male. If the calyx isn't raised on a small short stem then it's probably a female.

Third Early Sexing Method
'Force-flowering' is probably the best early-sexing method. To force-flower a cannabis plant, simply take a cutting and place it in a cup of water or a cloning medium, such as rock wool. Expose the cutting to 12 hours of light followed by 12 hours of total darkness. The cutting should flower and display its sex — however the plant must be mature enough to present its sex. An immature plant will not show sex because initial calyx development is not photo period related. Plants normally mature around the forth week of vegetative growth because sex is not genetically determined until the third week of growth.This also applies to 'feminized seeds,' which can, and often do, turn out to be male.** If your plants are exhibiting calyx development, then this is a suitable method of determining the plant's sex.